This invention relates to an integrated water pump assembly for internal combustion engines.
Water pumps for circulating of engine cooling water to internal combustion engine blocks are generally mounted to a housing structure supporting a rotary shaft in a rotary bearing assembly or unit, with the shaft projecting outwardly for interconnection to a driving member coupled to the engine drive system at one end and a water circulating impeller affixed to the opposite end of the shaft. The integrated assembly includes a housing secured to the rotary bearing structure or unit with a radial flange for mounting of the water pump assembly to the engine block. In the prior art, the housing is generally an annular plate-like member having an opening corresponding to the outer diameter of the bearing unit. The bearing unit may be formed with an outer collar within which a separate bearing member is press-fitted. Alternatively, the outer bearing race is extended and forms the outer wall structure of the bearing unit. Either the collar or the bearing wall is extended to receive a rotary seal at the impeller end. The housing is secured to the outer wall of the bearing unit at the seal end. For example, U.S. Pat. No. 4,768,923 discloses a prior art water pump housing assembly consisting of a bearing having the outer bearing race extended to receive a spring loaded seal unit. The housing plate is a generally annular plate having an opening substantially corresponding to the outer diameter of the outer bearing wall or race at the seal end. A wall of the sealing structure is also telescoped over the adjacent outer end of the outer bearing wall with the sealing wall and the edge of the pump housing, the bearing wall and the sealing wall interconnected to each other by a suitable weld or the like. Commercial prior art structures which have been used in connection with internal combustion engines have used similar bearing structures as well as the bearing structures having a separate collar with the bearing press-fitted into one end of the collar and a seal unit press-fitted or otherwise secured in the opposite end of the collar. A housing member generally in the form of a suitable flat metal plate having a central opening is secured to the end structure. In the commercial structures, the opening in a stamped housing has an outwardly opening small connecting flange defining the attachment opening. The connecting flange is of a length generally equal to the portion within which the sealing structure is located and is interconnected over the relatively small area of the flange. The interconnection, in the prior art, has suggested the use of a laser weld or alternatively a brazed joint as the method of securing the small metal flange to the collar or outer wall of the outer bearing race. A brazed joint is desirable as it allows the manufacturer or fabricator to utilize standard existing manufacturing processes that generally do not require specialized fixture systems.
Although the prior art has been employed in a satisfactory application to internal combustion engines for vehicles and the like, there is a continuing demand for pump housing structures which can be produced in a more cost effective structure and one which has the long reliable operating life. Thus, the component, fabrication, and assembly procedures and costs are integral considerations in connection with an appropriate design of a water pump. Further, it is highly desirable to permit recovery of certain component parts, such as the bearing member in the event damage occurs to the external assembly of the pump assembly without damage to the bearing, the seal unit or the like. Thus the integral structures, such as shown in the subject patent, would provide an integral welded or other fixed interconnection between the seal, the bearing structure and the housing and generally require scraping of the complete housing assembly because of the integral nature of the components.
Thus, there is a need for continuing improvement in the development of water pump housing assemblies for internal combustion engines and the like.